A monolithically integrated optical device. The device has a gallium and nitrogen containing substrate member having a surface region configured on either a non-polar or semi-polar orientation. The device also has a first waveguide structure configured in a first direction overlying a first portion of the surface region. The device also has a second waveguide structure integrally configured with the first waveguide structure. The first direction is substantially perpendicular to the second direction.

Provided is a semiconductor laser including: a core layer having an active layer and a diffraction grating layer optically coupled to the active layer; and paired clad layers arranged sandwiching the core layer, and formed with a waveguide along the core layer, and the semiconductor laser includes: a flat layer provided continuously with the diffraction grating layer along the waveguide; and a temperature control mechanism for controlling the temperature of the flat layer to a temperature different from that of the diffraction grating layer.

A multi-wavelength laser and a wavelength control method are disclosed. The multi-wavelength laser includes a waveguide, a first electrode, and a second electrode. The first electrode and the second electrode are disposed on the waveguide. The first electrode is electrically isolated from the second electrode. The first electrode includes a plurality of sub-electrodes, and every two adjacent sub-electrodes are electrically isolated. The second electrode is configured to amplify an optical signal in the waveguide by loading a current. At least one sub-electrode is configured to adjust a wavelength of the optical signal in the waveguide by loading a current or a voltage.

The present invention discloses a tunable semiconductor laser based on half-wave coupled partial reflectors. The laser comprises two resonant cavities; one resonant cavity is mainly composed of an optical waveguide, a first partial reflector and a second partial reflector, and the other resonant cavity is mainly composed of an optical waveguide, a first partial reflector and a second partial reflector. The resonant cavities are arranged along the same straight line and coupled to each other, and the two second partial reflectors in the two resonant cavities are connected by a common coupling waveguide. The present invention has the best single-mode selection, and an emitted wavelength can be switched between a series of channels; an optical grating needs not to be manufactured, and the structure is simple; and the laser has a high degree of freedom in coupler design and a great manufacturing tolerance and can realize large-scale digital tuning.

A laser comprising a narrow linewidth, comprising: a grating along a laser cavity; a laser waveguide having a plurality of waveguide sections corresponding to a plurality of grating sections, each of the plurality of waveguide sections having a ridge/mesa width for detuning the grating in each of the plurality of grating sections; and a plurality of contact electrodes contacting each of the plurality of waveguide sections, the plurality of contact electrodes for applying a different current to each of the plurality of waveguide sections to enable active feedback noise suppression.

A tunable laser device based on silicon photonics includes a substrate configured with a patterned region comprising one or more vertical stoppers, an edge stopper facing a first direction, a first alignment feature structure formed in the patterned region along the first direction, and a bond pad disposed between the vertical stoppers. Additionally, the tunable laser includes an integrated coupler built in the substrate located at the edge stopper and a laser diode chip including a gain region covered by a P-type electrode and a second alignment feature structure formed beyond the P-type electrode. The laser diode chip is flipped to rest against the one or more vertical stoppers with the P-type electrode attached to the bond pad and the gain region coupled to the integrated coupler. Moreover, the tunable laser includes a tuning filter fabricated in the substrate and coupled via a wire waveguide to the integrated coupler.

A narrow linewidth laser includes a passive ring resonant cavity, an FP resonant cavity, and a first gain region. The passive ring resonant cavity and the FP resonant cavity are combined to form an M-Z (Mach-Zehnder interference structure) compound external cavity structure, and the M-Z compound external cavity structure is at least used for providing wavelength selection and narrowing laser linewidth. The first gain region is provided on the outer side of the M-Z compound external cavity structure and is used for providing a gain for the whole laser. The narrow linewidth laser is simple in structure, high in side-mode suppression ratio, narrow in linewidth, and high in output power. By further integrating a PN junction region or MOS junction region, broadband and rapid tuning with low power consumption can also be achieved, and tuning management is simple.

A distributed feedback plus reflection (DFB+R) laser includes an active section, a passive section, a low reflection (LR) mirror, and an etalon. The active section includes a distributed feedback (DFB) grating and is configured to operate in a lasing mode. The passive section is coupled end to end with the active section. The LR mirror is formed on or in the passive section. The etalon includes a portion of the DFB grating, the passive section, and the LR mirror. The lasing mode of the active section is aligned to a long wavelength edge of a reflection peak of the etalon.

A modulator-integrated semiconductor laser (100) includes a semiconductor laser (101), an electro-absorption modulator (102), and an optical attenuator (103) that are monolithically integrated. The electro-absorption modulator (102) and the optical attenuator (103) are connected in series in a stage succeeding the semiconductor laser (101). A control unit (44) controls the DC bias voltage to be applied to the optical attenuator (103) to increase as temperature of the modulator-integrated semiconductor laser (100) rises.

A semiconductor laser includes an active region, a first distributed-Bragg-reflector region disposed contiguously with the active region, and a second distributed-Bragg-reflector region. The first distributed-Bragg-reflector region is formed contiguously with one side of the active region in a waveguide direction and includes a first diffraction grating. The second distributed-Bragg-reflector region is formed contiguously with to the other side of the active region in the waveguide direction and includes a second diffraction grating. The first diffraction grating includes recessed portions formed through a diffraction grating layer formed in the first distributed-Bragg-reflector region and convex portions adjacent to the recessed portions. The diffraction grating layer is made of a dielectric material.